Plan Download Page

SortaSenator Bostonian



The Bostonian class seems to be becoming more popular in the UK, partly I am sure due to the low key competitions put on by the Impington club at their meetings. The models are a handy size, simple to build and can fly very well. The Impington club fly Bostonians with a 14 gram minimum weight rule (the same as the AMA outdoor rules), which makes the class accessible to anyone (it is not uncommon for entries to require ballast as they have been built too lightly)

Main rules are, 16 inch max. wing span, 3 inch max. chord. and all flying surfaces must be covered on both sides. 14 inch max. fuselage length, which must incorporate a box with dimensions 1.5" wide, 2.5" high and 3" long. Clear windows must be carried with a projected area of at least 1 square inch. At least two rotating wheels must be carried spaced at least 2.5 inches apart so the model can sit on its undercarriage and ROG.

Many designs are cartoon versions of full size aircraft, and some others are caricatures of larger free flight sport models. The idea for the SortaSenator came from the well known SortaKorda Bostonian, which I think is an extremely cute model, and I thought I would give the same treatment to my favourite Keil Kraft rubber duration model, the Senator. This was the first rubber model I ever got to fly properly, back in the 1960s, so I have happy memories of it.

One stumbling block was the requirement in the Bostonian rules for a pair of wheels, whereas the Senator famously only has a mono leg. The solution was to hide the two wheels in the sub fins, so the model rests on those at the back, with the single wheel at the front. The three upper spars of the wing are a bit excessive I suppose, but I wanted to preserve the charactor of the original. I thought they might have a useful turbulating effect as well.

I am grateful to Russ Lister for building the prototype, before I managed to get round to building one myself and the the photos here are of his model. One modification made as a result of Russ's experiences was to make the front windows a little smaller to strengthen the forward fuselage (useful if you fly head first into a sports hall wall). Russ added a lower spar as well as the three upper ones, but reckons it was probably unnecessary. The choice is yours!

The best flight so far achieved is a rather impressive 75 seconds from a hand launch, though Russ is confident it will also ROG well.

important note

When I finally got round to building one of these in October 2014, I discovered an unfortunate error on the plan. Although the wing is exactly 3 inches chord, the span comes out slightly over 16", even when you take into account the angled wingtips. As the maximum span allowed for a Bostonian is 16", this is fairly serious!

Until I can find the time to redraw the plan, the obvious solution is to simply reduce the span of the wing centre section by 10mm, and leave the tips unchanged. That's what I decided to do on mine.



To read and print the pdf file you need Adobe Acrobat Reader, which is a free download from www.adobe.com

The pdf version of the plan is provided as three A4 sheets that have to be taped together. The plan should print off full size if you set your printer settings to A4 paper, even if it has got different sized paper in the printer. If in doubt, check against the 150 mm scale on the plan sheets.

Also available are three bitmap sheets in a zip file, each page being 1000 pixels wide. As the plan is drawn at 150 dpi, this means true image width is 6.67 inches (1000/150).

Finally there is single sheet bitmap file in case you want to tile it yourself, or have access to a large format printer.

Click here to download pdf file for A4 paper (64 KB)

Click here to download bitmap sheets for A4 paper (64 KB)

Click here to download complete plan as one bitmap image. (60 KB)





Peanut scale Short Seamew
Peanut scale Pottier 100 TS
Peanut scale Denight DDT
16 inch span Chilton DW.1
1/20 scale Curtiss F9C Sparrowhawk
Peanut scale Laird Speedwing Junior
1/20 scale Mitsubishi Ki 15 "Kamikaze"
Portsmouth Aerocar for twin rubber
Beech Super King Air 200 for twin rubber
22" span Short Seamew
Peanut scale Blackburn Ripon


Back to rubber plans index page

Back to home page